1. Field of the Invention
The present invention relates to a developing unit having a cooling duct, and an image forming apparatus which includes the developing unit.
2. Description of the Related Art
In an image forming apparatus, suppressing an increase in temperature of the developer within the developing unit during image formation processing is one effective method of obtaining a high-quality image. Japanese Patent Application Publication No. 2006-139045, for example, is known as means for suppressing an increase in the developer temperature.
In the case of the developing unit of Japanese Patent Application Publication No. 2006-139045, an increase in the developer temperature is suppressed using a cooling duct (heat sink); more specifically, a cooling duct made of aluminum having high heat conductivity is disposed adjacent to a developer restricting blade, for restricting the amount of developer on the developing roller, whereby the heat retained by the developer is transferred to the cooling duct via the developer restricting blade and thus dissipated.
However, although the cooling duct of the developing unit is capable of suppressing an increase in temperature, assemblability cannot be said to be favorable. More specifically, the cooling duct is incorporated within the developing unit in a state of being surrounded, not only by the frame of the apparatus main body of the developing unit but also by the supporting frames of the developer restricting blade and other members inside the developing unit. Installation of the cooling duct in the developing unit is therefore complicated.